1. Field of the Invention
The present invention relates to an improved image forming apparatus.
2. DESCRIPTION OF THE RELATED ART
Published Unexamined Japanese Patent Application 52-10142 discloses an image forming apparatus, such as a laser printer, for selecting one of a plurality of sheet storage sections, forming an image on a sheet fed from the sheet storage section selected and, when the sheet storage section involved becomes empty, automatically feeding a sheet from another sheet storage section, so long as the sheet is of the same size as that in the previous sheet storage section, irrespective of the direction in which it is fed in the apparatus, whereby a continued processing is carried out.
Published Unexamined Japanese Patent Application 60-144,255 discloses the technique of providing an auto-change selection input means for selecting a continuation sheet feeding mode and, when the sheet storage section involved becomes empty, automatically feeding a 25 sheet from another storage section when it is of the same size as that in the previous storage section and only when the auto-change selection input means is selected.
It is also known that, when a sheet storage section is empty, a sheet is fed from another sheet storage section, in which case use is made of only a sheet whose size is equal to or greater than that of the sheet in the former sheet storage section.
As set out above, even when a designated sheet storage section becomes empty, another sheet is continuously fed from another sheet storage section so long as it is equal to, or greater than, the former sheet with respect to its size.
In the prior art, one storage section stores plain paper sheets while, on the other hand, another storage section stores, for example, letter heads as sheets. Even if these sheets are to be used in a discriminating way, they are, so long as being equal to or greater than each other in size, fed to the image formation section irrespective of their different kinds. In the case where use is made of such a sheet as a letter head which is not desired to be fed continuously with the plain sheet, a continuous feeding function cannot be carried out in the conventional apparatus.